Internal pressure, free volume, molar refraction and excess molar thermodynamic properties of binary liquid mixtures of dimethyl sulfoxide + thiophene and dimetil sulfoxide + pyridine at 298.15K have been evaluated from the experimental measurements of densities, surface tension and refractive index. The relationship between the internal pressure, excess molar volume, molar refraction, and the molecular interaction of the bianry sistems is examined.
Internal pressure; free volume; thiophene; dimetilsulfoxide; pyridine